New installation in Ghent recovers energy and raw materials from wastewater

The purpose of the plant is to process the biomass that remains after treatment of domestic wastewater. This biomass is created by the growth of microorganisms that perform the purifying work and contain a wealth of energy and raw materials. Aquafin already produces completely green energy in the form of biogas on this basis. Somewhere in Antwerp, biomethane is currently also being produced for injection into the natural gas network.

The new plant, which is to be operational in 2026, will be able to utilize the added biomass to an even greater extent. Because it is a monoprocessor, the sludge is not diluted with other substances, allowing maximum recovery of energy and raw materials. The project is fully in line with Aquafin’s ambition to stop using fossil fuels by 2030 and in the long run to develop towards climate-neutral business operations.

Through a European tender procedure with a competitive dialogue, Aquafin went in search of a partner for the design, construction, financing and maintenance of the monoprocessor. The Dbfmo contract was recently awarded to the Besix – Indaver consortium, which is setting up a Special Purpose Vehicle (SPV) for this purpose.

“This state-of-the-art sludge treatment plant based on mono-incineration is an example in terms of circularity and net environmental impact. We have built up a portfolio of different industrial projects of similar or larger size worldwide, which benefit from the diversity of expertise available in the Besix Group: project financing, design, engineering, environmental considerations, construction, operation and maintenance. “Together with our partner Indaver, a top player active in many different types of waste treatment plants, we will provide a groundbreaking installation to our customer Aquafin,” said Pierre Sironval, Vice President of Besix Group.

“The circular economy only has a chance if everyone in the chain takes on their role and responsibilities. By closing high-quality material cycles, we can use raw materials again and again and contribute to the circular economy. Waste is no longer an unwanted end product, but a stream from which we create value. We will also value Aquafin’s water treatment sludge as much as possible in collaboration with Besix and with all parties involved by recycling phosphorus in the long term, ”adds Paul De Bruycker, CEO of Indaver.


The location of the new installation has been determined for some time. ArcelorMittal gives Aquafin a building right on site and buys 100% of the steam that the sludge treatment plant will produce. For the steel company, it is an additional power supply to their internal steam network, which further reduces the use of fossil fuels. The combination of a direct purchase of the entire steam production and a focus on raw material recycling makes this installation an example in Europe.

“To determine the ideal location, the ecological arguments were crucial to us. “We were based on a model where we could see for each possible location what the CO2 impact of all sludge transports in Flanders would be. It is important that the sludge transporters drive as few kilometers as possible through Flanders to get their cargo to its final destination. The valorisation opportunities for the energy produced in the possible places and in their surroundings were crucial in order to optimize for Flanders. The ‘carbon capture’ initiatives, which are being planned in the port of Ghent, have further strengthened ArcelorMittal’s file, ”says Jan Goossens, CEO of Aquafin.

“We are passionate about energy efficiency and circularity and continue to invest and launch new projects to fulfill our pioneering role in energy and climate change. By using the high pressure steam from Aquafin’s sludge treatment process in our steel production process, we make our energy consumption even greener. strength for the concrete implementation of our sustainability strategy towards an increasingly energy efficient company and even towards climate neutrality in 2050 ”, says Manfred Van Vlierberghe, CEO of ArcelorMittal Belgium.

Phosphorus recovery

In a follow-up phase, Aquafin plans to start full-scale phosphorus recovery, which is good for approximately 2,000 tonnes of pure phosphorus per year. By choosing mono-processing, phosphorus can be recovered more efficiently from biomass. Phosphorus is an important building block for life and an important part of our DNA, cell walls and bones.

We absorb it through our diet and it is therefore a basic component in mineral fertilizers for agriculture and horticulture. However, phosphate ores are a limited raw material and also a limited stock in Europe. Phosphorus ends up in domestic wastewater via the feed, from which Aquafin will recycle it sustainably with this new sludge treatment.

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